Effects of exercise on plasma myosin heavy chain fragments and MRI of skeletal muscle

Abstract

The effects of a single series of high-force eccentric contractions involving the quadriceps muscle group (single leg) on plasma concentrations of muscle proteins were examined as a function of time, in the context of measurements of torque production and magnetic resonance imaging (MRI) of the involved muscle groups. Plasma concentrations of slow-twitch skeletal (cardiac beta-type) myosin heavy chain (MHC) fragments, myoglobin, creatine kinase (CK), and cardiac troponin T were measured in blood samples of six healthy male volunteers before and 2 h after 70 eccentric contractions of the quadriceps femoris muscle. Screenings were conducted 1, 2, 3, 6, 9, and 13 days later. To visualize muscle injury, MRI of the loaded and unloaded thighs was performed 3, 6, and 9 days after the eccentric exercise bout. Force generation of the knee extensors was monitored on a dynamometer (Cybex II+) parallel to blood sampling. Exercise resulted in a biphasic myoglobin release profile, delayed CK and MHC peaks. Increased MHC fragment concentrations of slow skeletal muscle myosin occurred in late samples of all participants, which indicated a degradation of slow skeletal muscle myosin. Because cardiac troponin T was within the normal range in all samples, which excluded a protein release from the heart (cardiac beta-type MHC), this finding provides evidence for an injury of slow-twitch skeletal muscle fibers in response to eccentric contractions. Muscle action revealed delayed reversible increases in MRI signal intensities on T2-weighted images of the loaded vastus intermedius and deep parts of the vastus lateralis. We attributed MRI signal changes due to edema in part to slow skeletal muscle fiber injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Biochemical Measurement of Muscle Injury Created by Lumbar Surgery

“…17,28,29,[33][34][35][36] The individual variation in baseline CK, and peak magnitude in response to LS is also consistent with animal injury models 42 , and exercise induced injury. [17][18][19][20] Similar individual variation is characteristic of circulating troponins and myosin heavy chain. 28,29,31,32 A number of non-injury related factors have been found to affect baseline CK values including sex, race, body mass, and activity levels.…”

“…chain myosin 18,19 , and fatty acid binding protein. 20 There is an extensive literature on application of biochemistry for cardiac muscle injury and there has been a strong clinical impact.…”

Gene expression responses over 24 h to lengthening and shortening contractions in human muscle: major changes in CSRP3, MUSTN1, SIX1, and FBXO32

“…Responses to lengthening contractions may result in indices of muscle damage including Z-band streaming, loss in force generating capacity, soreness, swelling, and leaking of sarcoplasmic proteins into the blood (25,47,48,53,60). Nevertheless, some reports in the literature suggest that the changes listed above may be more related to rapid adaptation than damage (66 -68).…”

Developing Biologically-Based Assessment Tools for Physical Therapy Management of Neck Pain

“…24,30,66,69,70,115,120,143 Proteins implicated as potential soft tissue injury biomarkers include the cytoplasmic proteins, creatine kinase (CK) and myoglobin, 24,30,66,69,70,115,120,143 and proteins that make up the contractile apparatus, including myosin and skeletal troponin I. 85,100,101,120,143 Elevated levels of biomarkers have been successfully monitored to indicate muscle damage in other injuries, including intense exercise, trauma, and orthopaedic surgery. 24,30,65,66,85,102,115,120,121,143 Studies on neck injury are absent.…”

“…85,100,101,120,143 Elevated levels of biomarkers have been successfully monitored to indicate muscle damage in other injuries, including intense exercise, trauma, and orthopaedic surgery. 24,30,65,66,85,102,115,120,121,143 Studies on neck injury are absent. Our team is in the process of validating new biomarkers for peripheral muscle injury, starting by using a lumbar surgery model (where the muscle damage can be quantified) to measure the total CK, skeletal muscle CK (CK-MM), IL-6, and Oncostatin M. Our findings indicate that total serum CK peaks between 9 and 48 hours after surgery.…”